Almost a year ago, in the aftermath of the shootings in Newtown, Conn., a number of entertainment industry activists decried a vote that prevented the Senate from moving forward background check legislation. Some vowed to withhold support from Democrats who voted "No," including Sen. Mark Begich (D-Alaska) and Sen. Mark Pryor (D-Ark.), both of whom are in the midst of tough reelection races.

That was then, this is now.

On Wednesday evening, Cindy Horn and her husband, Walt Disney Studios chairman Alan Horn, are hosting a fund-raising event for Begich and Pryor at their home, and it has caught the attention of a collection of gun violence prevention groups.

In a letter sent to Cindy Horn on Wednesday afternoon, the groups urged her to cancel the fundraiser, or, in the alternative, that they instead raise funds for Senate candidates in tough races who voted for the background checks, including Sen. Mary Landrieu (D-La.), Sen. Kay Hagan (D-N.C.), Sen. Jeanne Shaheen (D-N.H.) and Sen. Mark Udall (D-Colo.).

The groups, including Women Against Gun Violence, the California Chapters of the Brady Campaign to Prevent Gun Violence, the Violence Prevention Coalition and Moms Demand Action for Gun Sense in America, wrote to Horn that "when Senators from far-flung places come to California to fuel their campaigns, we hope that you will remind them that you're not their personal ATM. You have a right to ask why they deserve their support.

"In particular, you have every right to ask why they helped a Republican minority defeat a Democratic majority and a Democratic president and vice president who worked their heart out on this chance for reform -- which may not come again for years."

The groups asked in their letter, "Is 'Democrat' merely a box on a ballot, to be checked at any cost?"

Among those who signed the letter were Margot Bennett, executive director of Women Against Gun Violence; Dallas Stout, president of the California Brady Campaign Chapters; Kaile Shilling of the Violence Prevention Coalition of Los Angeles, and Catherine Stefani, California chapter leader of Moms Demand Action.

In a year since the legislation stalled out, the political landscape has shifted into one that seems much more difficult for Democrats, with a challenge to raise money to match an expected onslaught from the right.

Contribution levels to the event start at $2,000 per person and go to a maximum of $10,400, with money going to a joint fund for their campaigns, according to a copy of the invite. Cohosts of the event include the Horns, MPAA chairman Chris Dodd and Universal's Ron Meyer and Jeff Shell. Alan Horn was out of town and not expected to attend, even though he is among the hosts, but his wife, Cindy, is a longtime political activist, particularly on environmental issues.

A spokesman for the studio declined comment.

One donor, who asked not to be identified, said that support for Begich and Pryor reflected a more pragmatic reality of this year's midterms for incumbents in red states: Withholding money would only increase the chance that a Republican conservative would be their successor, perhaps costing Democrats a valuable majority and stalling efforts on a host of other issues important to progressives. "It is a philosophical question," the donor said.

The donor noted that also scheduled to attend the event as a "special guest" was Sen. Amy Klobuchar (D-Minn.), who is not facing reelection. Her support of background legislation, however, would signal a message of unity among Democrats despite the differences on gun control.

As unlikely as it was that the Horns would cancel their event at the last minute, it is more likely that they and many other Hollywood Democrats will support the list of candidates who did vote for background checks. In fact, the Horns are hosting President Obama for an event, also at their home, on May 7 to raise money for Senate and House candidates.